The document discusses various aspects of tobacco production including types of tobacco, growing regions, cultivation practices, and harvesting. It notes that tobacco is an important cash crop grown for its leaves, which are most commonly used as a drug smoked in various forms. Proper plant management practices such as soil management, watering, weeding, topping, and de-suckering are described to maximize tobacco yield. Harvesting occurs 90-120 days after transplanting and can involve either priming of individual leaves or cutting the entire plant.
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
Tobacco intercultural operations
1. Tobacco is an important cash crop which is grown for its leaves.
It can be consumed, used as a pesticide and, in the form of
nicotine tartrate, used in some medicines.
It is most commonly used as a drug.
It is smoked as pipe, cigar, cigarette or hookah, used as snuff or
chewed as a quid in many forms.
Tobacco belongs to Solanaceae family (nightshade family). It is
herbaceous annual plant.
Tobacco is a tropical plant but can be grown in wide range of
climates.
2. The most tobacco growing countries are china, India,
Brazil, Pakistan, Argentina, Bangladesh, Japan, and
Germany.
In Nepal it is grown in eastern terai region namely Bara,
Parsa, Rautahat, Sarlahi, Dhanusha, Mahottari, Saptari,
Siraha districts.
Cultivated species are classified into 2 species.
Nicotina tabcum
Nicotina rustica
The NARC released variety of tobacco is Belachapi-1 and
recommended region for this variety is terai.
3. Plant management is a system of managing all the conditions
and criterions required for over all development and higher
yield of crop/ plant.
It consists of soil structure maintenance for optimum air
entry (soil aeration), regulation of plant stand, optimum plant
population, water management, nutrition regimes, weed
control and pest control.
It is a series of practices for bringing up higher yield of any
plant.
Tobacco needs suitable plant management practices that
uplift the production. The plant management practices of
tobacco includes soil loosening, water management, weed
management, topping, de- suckering.
4. Tobacco is quick growing crop, becomes ready to harvest in 90-120
days after transplanting. So it requires good aeration for growing
roots.
The size of root mainly determines the yield of crop.
The smaller the size of root the less water it uptakes resulting
comparatively low biomass. For this reason soil loosening are
preferred immediately after seedling are rooted which is about a week
after transplanting and are stopped before the tobacco plants cover the
space between rows.
Seedlings are susceptible to poor aeration and water logging
condition so there may be 3-8 soil loosening followed by weeding.
Loosening helps in better root growth, better canopy is established
and increases the infiltration rate because loosening disturbs the
crustation.
5. It consists of removal of the terminal bud with or without some of the
small top leaves just before or after the emergence of the flower head.
15-20 cm from upper most leaf removed.
This practice stimulates the development of the remaining leaves.
It gives a uniform quality product and prevents excessive coarseness in
tobacco.
It prevents the plants from producing seeds and allows carbohydrates and
other nutrients to go towards vegetative part instead of reproductive.
This practice cause thickening of leaves and increase their body.
It also helps in increasing nicotine content in upper leaves.
Topping causes uniform ripening of leaves and high quality leaves.
6. Stage of topping according to type of tobacco
Type of tobacco Stage of topping
Flue-cured At flower head
Burley 12-24 leaves level
Cheroot 14-16 leaves level
Cigar filler 12-14 leaves level
Hookah and chewing 8 leaves level
Natu At flower head
7. When the plants are topped, apical dominance is broken and lateral
buds, called sucker develop. The practice of removing these suckers is
called de-suckering.
This practice can be done by manually, using chemicals such as maleic
hydrazide.
Manual method is time consuming and cumbersome.
Removal of suckers should be done before they become large enough
to restrict the development of leaves.
De-suckering is conducted 5-6 times at an interval of a week.
The main aim of topping and de-suckering operations is to divert the
energy and nutrients of the plant from floral head to leaves which
influence the yield and quality of tobacco.
8. Irrigation is the artificial application of water to the field for the purpose of
overcoming critical stages in plant and ultimately to increase the plant yield.
The irrigation requirement depends upon the type of tobacco, soil texture and
environment.
The daily water demand varies from 0.15-0.625 cm depending upon crop
stages and agro-ecological conditions.
Irrigation scheduling can be made depending upon the moisture depletion
from soil, critical stages of plant and soil texture.
The critical stages in tobacco are knee high to bloom stage. During this period
sufficient level of soil moisture should be maintained for achieving higher
productivity.
In light soils 6-7 irrigations are required for flue cured tobacco.
9. First irrigation is given at three weeks after planting.
Tobacco needs light but frequent irrigations. The maximum requirement of water is
after one month of transplanting and low requirement after flower budding.
The optimum soil moisture to be maintained is 70% of field capacity before
blossoming and 40% of field capacity after blossoming.
Use of quality water is very important in tobacco. High chloride containing water
should be managed properly because it reduced the burning capacity of tobacco.
Excess chlorides in tobacco inhibits the leaf burn, reduce leaf storage capacity, leads
to two faced leaves which ultimately results in low pricing index.
Too much water in the field reduces the fertilizers efficiency, causes the leaching of
nutrients from soil.
So drainage is equally important as irrigation.
10. Weed control is an important production practice in tobacco
since weed competition for moisture and nutrients may result
in yield losses.
In addition to reduced yields, weeds may also be a serious
source of foreign material in mechanically harvested tobacco.
Good weed control in tobacco is best achieved by utilizing all
available methods of weed control in an integrated program.
11. 1.Sanitation
Many of the problem weeds in tobacco are the result of seed
produced in the field during the preceding crops or seed blown into
the field or onto plant beds.
Preventing weeds from producing seed in these areas may aid in
reducing weed problems in succeeding tobacco crops.
Destroying weeds around the plant bed area as well as utilizing
natural or artificial windbreaks will reduce weed problems.
Fumigation is done to prevent contamination of weeds in the bed.
12. Orobanche which is a root parasite and is a menace to the
tobacco crop is kept down by hand pulling.
This weed derives all nourishment from tobacco plant.
The only way to control this weed is to collect and destroy
before seed formation.
13. Crop rotation is important in handling weed problems in
tobacco, and in disease and nematode management systems.
Large-seeded broadleaf weeds, including
Cocklebur, Morningglory, Jimsonweed, and Sicklepod; and
small-seeded broadleaf weeds such as ragweed and hairy
galinsoga are not controlled by most tobacco herbicides.
Perennials are difficult to control in tobacco.
Rotations that include corn, cotton, sorghum or soyabeans
will help to reduce weed pressure in tobacco field.
14. Crop competition can be an effective tool in tobacco weed management.
Tobacco is a rapidly growing crop and the large leaves shade weeds.
Use good cultural practices to promote rapid tobacco growth, and use as
narrow rows as recommended to help shade weeds thus reducing weed
infestation in the tobacco field.
5.Chemical method/ herbicide application
Soil application of ethylene di bromides @ 2.5ml per m2 is practiced to
control severe parasitic weeds like Orobanche ramose and Orobanche
minor.
Similarly herbicides like alchlor, diuron, simazine, atrazine, pendimethalin
etc can be used as pre-plant or pre-emergence.
15. Harvest is the process of gathering the economic part of the
plant.
The stage of maturity and the methods of harvesting differ with
the type of tobacco.
The tobacco leaves do not ripe uniformly. Ripening starts from
lower to upper leaves.
The ripening process of tobacco consists of deposition of starch
and elimination of green matter. Change in color of leaf from
green to slightly yellow color is the time for harvesting.
It starts 90-120 days of transplanting.
The number of days from transplanting to harvest will vary
considerably by variety and growing season.
16. There are two methods of harvesting tobacco.
1. Priming
The method of harvesting properly matured leaves leaving some leaves which
are not fully ripened for better quality is called priming.
Priming requires several picking and harvest period for prime leaves may last
for 3-6 weeks.
Picking starts from lower most leaves which mature first and continue until the
uppermost leaves are ripened.
Each time 2-3 leaves are harvested at weekly interval. The entire harvest is
completed in about 5-6 priming.
Priming begins after 14-21 days of topping.
After harvesting the leaves are strung on bamboo stick of about 1.5 m length
at the rate of 60-80 leaves per stick and taken to barn for curing.
17. Hookah, bidi, cigar, cheroot and chewing tobaccos are harvested by
cutting the entire plant close to the ground with sickle when middle
leaves show the first tinge of yellow.
The time of cutting stalk depends upon the type of tobaccos.
Harvest bidi tobacco when majority of top leaves develop red rusty spots
known as spangles.
cigar and cheroot tobacco are harvested when the leaves turn yellowish
green and become brittle which breaks on folding.
Harvesting of chewing tobacco is done when the leaves develop
pronounced puckering and hookah tobaccos are harvested when there is
indication of yellowish brown spots of puckering on leaves.
The stalk is then hung upon a lath or stick. A lath or stick holds 6-8
stalks. Leaves are not removed from the stalk until curing is completed